Kalcul
mental calculation tutor for KDE
Kalcul is an application which helps children at the age of 6 or above to
improve their mental calculation skills. The children can choose between a
practice mode in which it is given random mathematical exercises of a certain
operation(+, -, x or /) and a Level mode in which it has to solve existing
levels which could have been created by a teacher or the parents using the
built-in Level Editor.
http://edu.kde.org/kalcul/